I am almost certain we carried our own beer into GL back in the early 80's. I remember standing in line for the log ride with beer in hand not purchased from the park. I know this has nothing to do with CP and their rules. Things were pretty wild there then, but we had a lot of fun!
As for CP, I always have beer at my room or in CV. I have purchased 12-packs at the camp store, including closing weekend. I don't know about the legal issues of walking around in "public" outside the park, but I'm sure you are fine in your room or camp site. Otherwise, I'm an outlaw too. Though, I have made many strolls out to the pier at lighthouse point with beer in hand. 